Lead Tracking Of Implantable Cardioverter-Defibrillator (ICD) And Cardiac Resynchronization Therapy (CRT) Devices

Abstract

Lead Tracking of Implantable Cardioverter-Defibrillator and Cardiac Resynchronization Therapy Devices improve upon the process of implantation of ICD-CRT devices, placing their leads, and improving the information fed back to the device and/or clinician. Tracking of the placement of the leads during implantation is accomplished along with monitoring the leads once implanted. Benefits include reducing the risk and complication rate, simplifying implantation procedure, and enabling the extraction of vital data not previously available. Leads are tracked to at least minimize the need to use fluoroscopy. Three dimensional tracking ( 10 ) is employed to facilitate obtaining of data that allows the surgeon to better visualize lead insertion and placement. Placement of the leads during a procedure requires use of an external tracking component along with means and method for tracking the implantable leads. Transmitting antennas ( 10, 110 ) are provided, equal in number to the number of degrees of freedom of tracking required. A link ( 50 ) between the sensor ( 70 ) and the computation unit ( 40 ) can be wired or wireless. Once leads are implanted, heart wall motion must be monitored via the tracking of the leads within a clinical or home environment. Such tracking of the leads may be accomplished in real time.

1 . A system for tracking absolute position and orientation of an implantable cardiac ICD lead during and after implantation comprising an ICD lead having a magnetic tracking sensor affixed thereto, a magnetic field generator, and a computer programmed to determine the sensor's X, Y, Z coordinates and pitch and yaw orientation in real time. 
   
   
       2 . The system according to  claim 1 , wherein an absolute frame of reference is established by said external magnetic field generator. 
   
   
       3 . The system according to  claim 1 , wherein said sensor on said lead is used to assist implantation of said lead. 
   
   
       4 . The system according to  claim 1 , wherein a single lead with a magnetic sensor measures real time motion of an atrium outer wall of a heart to which said lead is attached. 
   
   
       5 . The system according to  claim 4 , wherein absolute motion of the atrium wall is employed to monitor overall cardiac function of a patient. 
   
   
       6 . The system according to  claim 5 , wherein cardiac function is monitored over time to (a) establish baseline cardiac output, (b) to monitor gradual cardiac degradation, (c) to initiate pacing, or (d) to alert medical professionals when cardiac performance falls below preset limits. 
   
   
       7 . The system of  claim 4 , wherein absolute motion of the atrium is sensed, and, responsive to values outside preset limits, pacing is initiated. 
   
   
       8 . The system of  claim 4 , wherein absolute motion of the atrium is sensed, and responsive to values outside preset limits, pacing is ceased. 
   
   
       9 . The system of  claim 4 , wherein absolute motion of the atrium is used to optimize pacing for maximum cardiac output and/or to minimize power drain on the ICD. 
   
   
       10 . The system according to  claim 1 , wherein one or more additional leads are implanted within a heart to provide multiple electrical stimulation points and/or to provide absolute positional real time information at an implantation site. 
   
   
       11 . The system according to  claim 10 , wherein absolute position from multiple leads is employed to optimize voltage, current and/or lead to lead timing of electrical stimulus from an ICD to optimize cardiac output, or to minimize ICD power drain, or to interrupt uncoordinated cardiac activity and/or to resynchronize cardiac rhythm. 
   
   
       12 . The system according to  claim 1 , wherein an additional magnetic tracking sensor is located inside the ICD or outside the ICD but subcutaneously above ribs to provide a patient-based frame of reference. 
   
   
       13 . The system according to  claim 12 , wherein said additional sensor is employed to detect patient body motion and improve an algorithm employed to determine cardiac motion. 
   
   
       14 . The system according to  claim 12 , wherein said additional sensor is employed to detect patient respiratory motion in order to improve an algorithm employed to determine cardiac motion. 
   
   
       15 . The system according to  claim 12 , wherein said additional sensor is used to monitor patient respiratory motion in order to identify if a patient has ceased breathing. 
   
   
       16 . The system according to  claim 15 , wherein the ICD initiates electrical stimulation responsive to sensing respiratory function outside preset parameters to reestablish respiratory function. 
   
   
       17 . The system according to  claim 16 , wherein an additional electrical stimulation lead is placed in a body (outside a heart thereof) to stimulate the body to reestablish respiratory function. 
   
   
       18 . The system according to  claim 1 , wherein a large inductive coupler is located within the ICD to provide electrical power from a magnetic field generated by the magnetic field generator, said electrical power being supplied to the ICD to power the ICD and/or to extend the ICD's battery life. 
   
   
       19 . The system according to  claim 1 , wherein the magnetic field generator is located near a patient during periods of time when said patient is asleep. 
   
   
       20 . The system according to  claim 1 , wherein the magnetic field generator is located on or inside a patient's chair, wheelchair or hospital bed. 
   
   
       21 . The system according to  claim 12 , wherein the magnetic field generator is located on or inside a patient's chair, wheelchair or hospital bed. 
   
   
       22 . The system according to  claim 1 , wherein the magnetic field generator is portable and can be moved with a patient. 
   
   
       23 . The system according to  claim 12 , wherein the magnetic field generator is portable and can be moved with a patient. 
   
   
       24 . The system according to  claim 1 , wherein an accelerometer is placed on the lead adjacent to the magnetic tracking sensor so that acceleration and displacements are simultaneously measured.